The positive regulator of gene expression specified by the bacteriophage lambda Q gene is proposed to work by counteracting a transcriptional termination event. We intend to test this hypothesis and determine the detailed mechanism of action of this regulator by purifying it and investigating its activity in a purified system with defined components. We also will attempt to determine the mechanism by which the bacteriophage lambda repressor is inactivated during induction of a lysogen. BIBLIOGRAPHIC REFERENCES: Jeffrey W. Roberts, 1976. "Transcription Termination and its Control in E. coli" in RNA Polymerase, Cold Spring Harbor Laboratory, pp. 247-271. Roberts, J.W., C.W. Roberts, S. Hilliker, and D. Botstein, 1976. "Transcription Termination and Regulation in Bacteriophages P22 and Lambda" in RNA Polymerase, Cold Spring Harbor Laboratory, pp. 707-718.